While there isn't a single blood test specifically for a fever, a set of blood tests, often referred to as a "fever panel" or "fever workup," is commonly performed to help determine the underlying cause of the fever. The Complete Blood Count (CBC) is a central part of this investigation.
Here's a breakdown:
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Complete Blood Count (CBC) with Differential: This is a key test. It measures different components of your blood, including red blood cells, white blood cells, and platelets. The differential portion identifies the types of white blood cells present. An elevated white blood cell count often indicates an infection. Specific types of white blood cells (e.g., neutrophils, lymphocytes) can point to bacterial, viral, or parasitic infections.
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Other commonly included tests in a fever workup:
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Erythrocyte Sedimentation Rate (ESR): This test measures how quickly red blood cells settle in a test tube. A high ESR can indicate inflammation in the body, which can be caused by infection, autoimmune diseases, or other conditions.
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Malaria Parasite Detection (MP): If malaria is suspected based on travel history or other risk factors, this test is crucial to identify the presence of malaria parasites in the blood.
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Widal Test: This test is used to detect antibodies against Salmonella typhi and Salmonella paratyphi, the bacteria that cause typhoid fever. However, its accuracy is debated, and other tests are often preferred now.
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Blood Culture: If a bacterial infection is suspected, a blood culture can identify the specific bacteria causing the infection.
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Urine Routine Examination: Although not a blood test, a urine test is often ordered as part of the workup to rule out urinary tract infections.
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Other Potential Tests: Depending on the patient's symptoms, medical history, and geographical location, other blood tests might be performed, such as:
- Liver function tests (LFTs)
- Kidney function tests (KFTs)
- Viral serology (e.g., dengue, chikungunya, HIV)
- Blood film for parasites other than malaria
In summary, while a Complete Blood Count (CBC) is a crucial component, investigations for a fever usually involve a panel of blood tests tailored to the individual's specific circumstances to find the cause of the fever.
